Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Datacenters, facilities with network equipment and servers for data processing and/or storage, are prevalent and essential to provide a myriad of services and applications for business, communications, academic, and government systems. To provide a reliable and scalable computing infrastructure, the network capacity of datacenters is typically provisioned for busy-hour load, and thus datacenters consume a large amount of energy. The Report to Congress on Server and Data Center Energy Efficiency by the Environmental Protection Agency in 2007 assessed trends in the energy use and energy costs of datacenters and servers in the U.S., and outlined existing and emerging opportunities for improved energy efficiency. It is estimated that datacenters and servers consumed about 61 billion kilowatt-hours (kWh) in 2006 (1.5 percent of the total U.S. electricity consumption) for a total electricity cost of about $4.5 billion. The energy use of datacenters and servers in 2006 is estimated to be more than double the electricity that was consumed for this purpose in 2000 and could nearly double again in 2011 to more than 100 billion kWh, representing a $7.4 billion annual electricity cost.
The provisioning for busy-hour loads in a mismatch between datacenter utilization and power consumption. Numerous studies have shown that datacenter servers rarely operate at full utilization and it has been well established in the research literature that the average server utilization may often be below thirty percent of the maximum utilization in datacenters. The high operational costs and the mismatch between datacenter utilization and power consumption have spurred interest in improving datacenter energy efficiency. Reducing a number of available resources may not be acceptable from a customer experience perspective, however. Furthermore, taking resources offline may bring additional challenges in terms of planning, execution, and optimization.